1. Field of the Invention
The present invention relates to a recording apparatus such as a color electrophotographic recorder and its recording method.
2. The Prior Art
Conventional recording apparatus of this type, color recorders such as "multiple-development and single-transfer type" and "multiple-development and multiple-transfer type" are known. In the multiple-development and single-transfer type, the electrostatic latent images formed sequentially on an image carrier, such as an electrophotographic photosensitive member, are developed by developers of different colors to form a multicolor toner image. Then, the images are simultaneously transferred to a record sheet. In the multiple-development and multiple-transfer type, electrostatic latent images are sequentially formed, developed and transferred to form a multicolor toner image on a recording sheet.
The multiple-development and single-transfer type is excellent in recording speed and superposing accuracy of the images, but has drawbacks such as a disorder of images and the mixing of different toner colors. There drawbacks occur because of the use of separate developing units when sequentially unfixed images are superposed on an electrostatic recording medium they can be easily disturbed. Because of these drawbacks this type of a recording apparatus has not yet been put to practical use.
There is proposed in Japanese Patent Application No. 233407/1982 a color recording apparatus which has a process for solving such drawbacks by preventing the same portions from being redeveloped. However, when this apparatus is used as a monochromatic recorder for a computer output unit, cannot improve the quality of images and recording speed as is needed.
It is known that the above-mentioned drawbacks are reduced but, not completely solved, by electrostatically preventing the mixing colors of toners.
It is also known that no mechanical contact between the toner and the image to be developed on the sheet can exist. Therefore, a flying developing method has been developed. This method can prevent mixing of colors and thus subsequent contamination and also can provide excellent gradation and color recording as compared with the conventional magnetic brush developing method. However, this method is apparently undesired for the purpose of copying a document full of characters. Consequently, a recording apparatus which can produce quality color and monochromatic images.